1. Field of the Invention
The present invention pertains to the art of refrigerators and, more particularly, to a system for equalizing pressures between inside and outside of a refrigerator.
2. Discussion of the Prior Art
In general, a refrigerator includes a first or freezer compartment for maintaining foodstuffs at or below freezing, and a second or fresh food compartment, in fluid communication with the freezer compartment, for maintaining foodstuffs in a temperature zone between ambient and freezing temperatures. A typical refrigerator includes a refrigeration system having a compressor, a condenser, a condenser fan, an evaporator coil, and an evaporator fan.
In operation, temperature sensors are provided within the refrigerator to measure internal temperatures of the appliance. When a door associated with either compartment is opened, the temperature within the respective compartment will rise. When the internal temperature of the refrigerator deviates from a predetermined temperature, the refrigeration system is caused to operate such that the temperature will return to a point below a consumer selected set-point. In order to return the compartment temperature to this point, the refrigeration system is activated.
A supplement to compressor operation is the addition of a damper located between the evaporator and the fresh food compartment. Operation of the damper is controlled such that cool air is permitted to flow from the evaporator to the fresh food compartment. In some arrangements, a fan is mounted adjacent to the evaporator to aid in establishing the air flow. Accordingly, if the temperature of the fresh food compartment rises above the set-point, the damper is operated to allow the passage of cooling air from the evaporator compartment to the fresh food compartment.
In any case, due to operation of the refrigeration system or otherwise cooling of a refrigerator compartment, a temperature gradient develops between inside and outside of the refrigerator. As doors are opened and closed on a refrigerator in operation, especially in a warm, humid environment, a pressure differential can be created from outside the refrigerator to inside. This pressure differential results in the doors being hard to open. Certainly, it is desirable to maintain a fairly consistent opening force requirement. To this end, there exists a need in the art for a system to equalize pressures inside and outside a refrigerator in order to control the level of force needed to open a door of the refrigerator. Although pressure equalizing systems have been proposed in the art, the need still exists for a reliable, cost efficient, pressure relief system, particularly one which regulates a pressure controlling air flow in an effective manner.
The present invention is directed to incorporating a pressure relief system in a refrigerator in order to allow for easier opening of a door of the refrigerator. The system serves to relieve an excessive pressure differential or vacuum condition that develops due to warm air entering the refrigerator and then cooling. In accordance with a preferred embodiment of the invention, the pressure relief system includes a check valve having an orifice with a flexible membrane attached thereto. An insulation portion of the pressure relief valve, which is foamed into the cabinet, spans from the fresh food compartment to the cabinet top. The pressure relief valve includes a portion in the fresh food compartment that directs air towards the rear cabinet liner for moisture condensing measures. The valve also includes an adapter which is secured to the cabinet top and provides a mounting surface for an air return assembly. The air return assembly is an injection molded housing which includes an opening, preferably including a flexible membrane.
In essence, in an effort to relieve the pressure differential, the pressure relief assembly defines a duct which serves as a pathway for pressure relief from one chamber of the refrigerator to the surrounding environment. By incorporating a check valve arrangement, the pressure relief function is performed automatically as needed.